I have two small angelfish in a ten gallon tank (I know, too small). *they have a small amount of white fuzz on top of their heads (where the hump is on the male). *Should I use a fungicide, and if so, which one? *The other fish (four neon tetras and a small cat) don't seem to have this. *thanks for your help! * BTW, this is a new tank, less than a week old.